Fluid stream vacuum pump



Feb. 24, 1948. J. w. TILLS FLUID STREAM VACUUM PUMP Filed April 12, 1945 T S hee-rls-Sheet 1 14 ttorneys FLUID STREAM VACUUM PUMP Filed April 12, 1945 7 Sheet-Sheet 2 Q i 1: lnuir ltgg tlorney Q,

Feb. 24, 1948. Q lLLs 2,436,704

FLUID STREAM VACUUM PUMP Filed April I2, 1945 7 Sheets-Sheet 5' A ttorney 5 Fe. 24, 1948. J. w. TILLS FLUID STREAM VACUUM PUMP Filed April 12, 1945 '7 Sheets-Sheet 4 Altorneybv mag "7 Sheets-Sheet 5 J. W. TILLS FLUID STREAM VACUUM PUMP Filed April 12, 1945 Feb 4, $94.

Altorney mm E Feb. 24, 1948. w,

FLUID STREAM VACUUM PUMP Filed April 12, 1945 7 Sheets-Sheet 7 A ttorneyg.

Patented Feb. 24, 1948 UNITED STATES PATENT.

OFFICE Application April 12, 1945, Serial No. 587,869 In Great Britain April 18, 1944 19 Claims. (01. 230-101) This invention relates to fluid stream vacuum pumps.

One object is to increase pumping speed. Another object is to provide a pump which will operate against relatively high forevacuum pressures.

A further object is to provide a pump which is suitable for pumping ofi large volumes of vapour of hydrocarbon solvents such as benzol.

A still further object is the provision of a pump of robust and durable construction especially suitable for many industrial processes.

These and other objects will become apparent from a perusal of the following description and the drawing annexed hereunto.

In the drawing: Fig. 1 is a side elevation, partially broken out-and in section, showing a vessel and ancillary parts for working fluid supply and storage; Fig. 2 is a horizontal section on the line I l--ll of Fig. 1; Fig. 3 is a vertical fragmentary detail section, partly in elevation, showing the construction of a fluid stream pump in its relation to the vessel and other parts shown in Figs. 1 and 2; Fig. 4 is a general arrangement in side elevation showing one form of apparatus complete with backing pump; Fig. 5 is a general arrangement in side elevation, partially broken out and in section, showing another form of apparatus connected to a vessel to be evacuated and to a backing pump; Fig. 6 is a. medial vertical section of one form of vapour stream nozzle and boiler unit; especially suitable for use at the lowg est pressure stage of a cascade fluid stream pump; Fig. 7 is a medial section corresponding to Fig. 6; Fig. 8 is a medial section of one form of vapour stream nozzle and boiler unit especially suitable for use at an intermediate pressure stage of a cascade fluid stream pump; Fig. 9 is a medial section of one form of liquid discharge nozzle especially suitable for use at the highest pressure stage of a cascade fluid stream pump; Fig. 10 is a wiring diagram.

Referring more especially to Figs. 1 and 2, a substantially gas-tight steel vessel ID has a lid ll gas-tightly secured theerto. An electric mo-v tor l2 mounted on lid ll drives, by way of a belt l3, a spindle M of a stuffing box assembly secured to the wall of vessel [0 so as to partially project therethrough. Spindle I4 is connected through a coupling] 5, preferably flexible, to a multicylinder piston pump it.

Pump I6 is fed by an inlet pipe l1 and discharges through a pipe l8 to a blow-ofi or pressure release valve assembly I 9 supported, from the wall of vessel l0 and having an adjustment spindle 20 passing through a stuffing box to atmosphere and terminating in a handwheel 2|.

A pipe 22 extends between valve assembly l9 and a flange 23 to which it is secured by welding or brazing. Flange 23 is bolted or otherwise secured to the inner face of a pad 24 built into and extending through a wall of vessel H). A flange 25, to which is attached one end of a-pipe 2B, is secured to the outside of Dad 24. Pipe 26 (Fig. 3) is connectable to a liquid pressure indicator 28 by way of a valve 21. A pipe 29 is connectable to a branch of pipe 26 by way of a valve 30.

Pipe 29 leads from valve 30 to an outer wall 3| of a cooling jacket surrounding a cone-shaped body 32 of a fluid stream pump;

Lid I l supports a transformer having a primary winding 36 energisable from the electric supply main and a low voltage (4 to 20 volts, by way of example) secondary winding 31. A centre tap of the secondary winding is grounded to the vessel and thence to the pump body 32.

A mechanical backing pump 38 (Fig. 4), driven by an electric motor 39, has its inlet connected by way of a forevacuum conduit 40 to a forevacuum enclosure formed above the level of liquid contained in vessel l0, within said vessel. The pump body- 32 has at its smaller diameter end an inwardly projecting portion of a forevacuum conduit 10 bolted to and supported from a pad "H on the lid ll.

A pipe 72 extends from the lowermost point at the forevacuum (small diameter) end of the pump body, by way of a valve 73 to a gas-tight collection vessel 14 having a draw-off valve 15.

A manifold 16, connected to the outer Wall 3| .at a point near the greatest diameter thereof provides communication between the cooling jacket around body 32 and three pipes l1, l8 and 19 by way of control valves 80, 8| and 82 respectively. w

A high vacuum connection I30 extends as a side arm from the large diameter cylindrical end portion of the'pump body 32 and terminates in a flange to which a flanged high vacuum conduit l3! may be secured.

An end plate 83 secured by bolts or other means (not shown) to the large diameter end of the pump body 32 by way of a flange 84 welded to said end.

Pipes l1, l8 and 19 extend through. bores in plate 83 into the interior of body 32 and supply, respectively a low pressure nozzle and boiler unit (Figs. 6 and 7), a medium pressure nozzle and boiler unit (Fig. 8), and a high pressure nozzle (Fig. 9) suitably supported within the interior of body 32.

Referring to Figs. 6 and '7, a low pressure nozzle and boiler unit is shown supported by a clip 85 from a base plate 86. The unit proper is constituted by a boiler case 81 of generally cylindrical shape having one end closed by a disc portion 88 and the ,,other outwardly flaredjn.a.conical position 88. .An electrical: conductorypreferably .copper strap may be conductively attached or united to valve block 95, by way of a lug I02.

A flash boiler is formed from a helically wound conduit 90 which may be of stainlesssteel. One end of conduit 90 is brazed into ,a connection .9I extending through a bore in end 88, secured thereto by a nut 92 .engagingl'oniaithreaded portion of the connection shank; andinsulatedby sets of mica washers 93 and 94.

The other end of conduit 90 is brazedinto a valve block 95, likewise insulatedly mounted from "and extending throughend 88. The valve block 95 is internally threaded-at its outer end and receives a threaded portionBfiof a piston valve having a. cylindrical portion '91 slidable inthe "last mentioned end portion of -conduit90. The valvecan be adjusted by-application of-a screwdriver to a slot-'98 whereby thecylindrical portion 91 is movable longitudinally of the endportion of conduit-90 to'vary the'efiective-area of a port presented by a'bore 99 in said conduit.

A deflector 'I00-is coaxially supported-with respect to the case 81 by a rodl 0| brazed to end 88.

Referring to Fig. 8, a medium pressure nozzle and boiler unit includes a helical conduit I03.

forming a. flash boiler-and a vapour discharge nozzle assembly. 'Saidassembly-comprises a nozzle block I 04-havinga conical bore I05 at one end coaxial with a counterbore I06of an axial bore 101, Disposed around-and'parallel withbore I01 is a plurality of'small bores I08.

A conical deflectorIOQ, adaptedto co-operate "with the surface presented "by'bore I 05 to provide a suitablepathfor-vapour, has'a cylindrical shank; portion I I0. Portion I I0 isa slidin fit in axial bore I 08"and.is "longitudinally adjustable "therein'by engagementof a tapped bore in its end with the shankrof a set'screw IIIto which the "head is brazed to the end of block I04.

Block I04 has a threaded shankportion II'2 .engageable in a socket H3. One endof conduit I03 passes through a radiakbore in the socket H3 and is attached to the socket by brazing. A screwed plug H4 is engaged in a tappedbore .in the socket.

An electrical conductor, such as copper strap "may be connected-to theoutside of block I04 by *alug I I5.

"The opposite end 'of conduit I-03passes into a socket IIIi through'a radial bore therein, and'is secured to the socket by brazing.

Referring to Figj9'aliquid discharge'nozzle may be formed on generallysimilar lines tothe nozzle assemblyofFig. 8- with the exceptionthat "apipe I I1 is'secured-"directly-"in-the end of the socket H3.

I Referring-again to Fig. "3, the endplate 84 *carries insulatedly'two terminals I I8 and H9 extending therethrough and "connected respectively by suitably insulated, preferably braided --or'other-semiflexibleconductors I20 and I2I to lugs I02 and I I5"onthe-low pressure nozzle and boiler unit and'the medium pressure'nozzle and "boiler unit respectively.

The endsof thesecondary" winding "31 of the recirculate the workingfluidused working fluid returning to tank 10 through conduit 10 under the influence of gravity.

heating currentto thelow pressurefiash boiler. Likewise-a second variable reactor I26 is connected in series with a switch I21 between terminal I23 on lid II and terminal II9 on plate 83,

for control of heating current to the medium j-pressure' flash boiler,

In operation, a working fluid, such as dibutyl "phthalate, is introduced into vessel I0 so as to .coverthe coils.36 and 31 of the transformer.

The backing pump 38 is started up and after a suitable forevacuum has been attained within 'vessel'IIland pump body 32, pump I6 is started up. Valve I9 may be adjusted until, with valves ZTand open, adesired liquid pressure obtains in pipe 29 as indicated in gauge 28. 15 to lbs/sq. inch is a convenient range from which to select a working pressure.

'Valves80, 8| and 82-may besetso that under known pressure liquid flows through pipes Ii,

"'18 and 19.

Finally the primary-winding of the transformer is energised, causing heavy secondary currents to how through conduits 90 and I03 when switches =fluid is collected in vessel'14. It can be drawn od, for less exacting uses, after shut down of 40 in vessel I4. The level in vessel I0 may be mainthe apparatus and breaking of the-vacuum withtained by supply from an evacuated reservoir by way of a float valve (not shown) if desired.

If little or no cracking'is encountered it may be preferable to keep valve I3 closed and to Referring to Fig. 5, there is shown a form of apparatus especially'suitable for'exhausting relatively large vessels which may be remotelydisposed from abacking pump.

A vessel I32, such as an impregnator, has a downwardly inclined vacuum connection I33, to

which is attached a conduit length I34 of similar diameter. Disposed within conduit length I34 is a nozzle and flash boiler'unit I35, which may be constructed forexample in the manner shown in Figs, 6 and 7. -The unit'I35 is supported from a plate 86 bolted to'a pad I36 surrounding an opening in the lower part ofthe conduit wall.

Other conduit lengths I3! and I38, of progressively smaller diameter may each have nozzle and boiler units, constructed for-example in the mannor shown in Figsifi' and 7.

The last conduit length isconnected to a back- 'ing pump I39 bya forevacuum conduit I40 and has a relatively large diameter depending branch i4I to which a working fluidreturn pipe I42 is connected.

Liquid working fluid under pressure, as described herein before is supplied from an assembly I43 including a transformer and liquid supply pump. Current'to the flash boilers may be controlled in any suitable" manner, such as by independent variable reactors.

all the boilers are shown as being connected in parallel to one end of a secondary winding of which the opposite end is grounded.

I claim:

1. In a fluid stream vacuum pump employing as working fluid an organic liquid having at room temperature a relatively low vapour pressure; nozzle means adapted to emit a stream of vaporised Working flu-id boiler means arranged to supply vapourised Working fluid to said nozzle means; and means to supply liquid working fluid to said boiler means at a pressure of at least lbs/sq. inch.

2. A fluid stream vacuum pump comprising a pump body having a high vacuum connection and a fore-vacuum connection respectively adjacent its opposite ends, a low pressure nozzle arranged within said body and directed towards the fore-vacuum end thereof, a high pressure nozzle arranged within said body between said low pressure nozzle and the fore-vacuum end of the pump body and directed towards said forevacuum end, means to supply vapourised working fluid to said low pressure nozzle, and means to supply working fluid in liquid phase to said high pressure nozzle.

3. A fluid stream vacuum pump comprising a conical pump body having a high vacuum connection and a fore-vacuum connection adjacent its larger and smaller ends respectively, a low pressure nozzle arranged within said body and directed towards said smaller end, a high pressure nozzle arranged with-in said body between said low pressure nozzle and said smaller end and directed towards s'aid smaller end, means to supply vapourised working fluid to said low pressure nozzle, and means to supply working fluid in liquid phase to said high pressure nozzle.

4. A fluid stream vacuum pump comprising an enclosed storage means forworking fluid, a conical pump body having a high vacuum connection and a fore-vacuum adjacent its larger and smaller ends respectively, a low pressure nozzle arranged Within said body and directed towards said smaller end, a high pressure nozzle arranged within said body between said low pressure nozzle and said smaller end, and directed towards said smaller end, boiler means to vapourise working fluid and adapted to supply vapourised working fluid to said low pressure nozzle, and means to supply working fluid in liquid phase from said storage means to said boiler means and to said high pressure nozzle,

5. A fluid stream vacuum pump comprising an enclosed storage means for working fluid, a conical pump body having a high vacuum connection and a fore-vacuum connection adjacent its larger and smaller ends respectively, a low pressure nozzle arranged within said body and directed towards said smaller end, a. high pressure nozzle arranged Within said body between said low pressure nozzle and said smaller end and directed towards saidsmaller end, boiler means to vapourise working fluid and adapted to supply vapourised working fluid to said low pressure nozzle, and means to supply working fluid in liquid phase under'pressure from said storage means to said boiler means and to said high pressure nozzle.

6. 'A fluid stream vacuum pump comprising an enclosed storage means for working fluid, a conical pump body having a high vacuum connection and a fore-vacuum connection adjacent its larger and smaller ends respectively, a low pres- In Fig. 10.

sure nozzle arranged within said body and directed towards said smaller end, a high pressure nozzle arranged within said body between said low pressure nozzle and said smaller end and directed towards said smaller end, a flash boiler arranged within said body and adapted to supply vapourised working fluid to said low pressure nozzle, and means to supply working fluid in liquid phase under pressure from said storage means to said flash boiler and to said high pressure nozzle.

7. A fluid stream vacuum pump comprising an enclosed storage means for working fluid, a conical pump body having a high vacuum connection and a fore-vacuum connection adjacent its larger and smaller ends respectively, an enclosed cooling jacket having an inlet and an outlet and disposed around said body, a low pressure nozzle arranged within said body and directed towards said smaller end, a high pressure nozzle arranged within said body between said low pressure nozzle and said smaller end and .directed towards said smaller end, boiler means'to vapourise working fluid and adapted to supply vapourised working fluid to said low pressure nozzle, means to supply working fluid in liquid phase under pressure from said storage means to said jacket inlet, and conduit means between said'j'acket outlet and said boiler means and to said high pressure nozzle.

8. A fluid stream vacuum pump comprising an enclosed storage means for working fluid, a conical pump body having a high vacuum connection and a. fore-vacuum connection adjacent its larger and smaller ends respectively, a low pressure nozzle arranged Within said body and directed towards said smaller end, an intermediate pressure nozzle arranged within said body between said low pressure nozzle and said smaller end and directed towards said smaller end, a. high pressure nozzle arranged within said body between said intermediate pressure nozzle and said smaller end and directed'towards said smaller end, boiler means adapted to supply vapourised working fluid to said low pressure and intermediate pressure nozzles, and means to supply working fluid in liquid phase under pressure from said storage means to said boiler means and to said high pressure nozzle.

9. A fluid stream vacuum pump comprising an enclosed storage means for working fluid, a conical pump body having a high vacuum connection and a fore-vacuum connection adjacent its larger and smaller ends respectively, a low pressure nozzle arranged within said body and directed towards said smaller end, an intermediate pressure nozzle arranged within said body between said low pressure nozzle and said smaller end and directed towards said smaller end, a high pressure nozzle arranged within said body between said intermediate pressure nozzle and said smaller end and directed'towards said smaller end, a flash boiler within said body adapted to supply vapourised workingjfluid to said low pressure nozzle, a second flash boiler within said body adapted to supply vapourised working fluid to said intermediate pressure nozzle, and means to supply working fluid in liquid phase under pressure from said storage means to said boilers and to said high pressure nozzle.

10. A fluid stream vacuum pump comprising an enclosed storage means for working fluid, a conical pump body having a high vacuum connection and a fore-vacuum connection adjacent its larger and smaller ends respectively, a low.

pressure nozzle arranged within said body and directed towards said smaller end,- arr-intermediate pressure nozzle arranged'within-said body between said low pressure nozzleand-said smaller end and directed towards said-smaller end, a high pressure nozzle arranged within said body between said intermediate pressure nozzle and said 11. In a fluidstream vacuum pump employing as working fluid an organic liquid having at room temperature a relatively low vapour pressure, a liquid jacketed body, nozzle means todischarge a stream of working fluid within said body for effecting pumping action, working fluid storage means, and means forsupplying working fluid to said nozzle means by way of the liquid jacket. v

12. In a fluid stream vacuum pump, a liquid jacketed body, nozzle means to discharge a stream of working fluid within said body for effecting pumping action, workin fluid storage means, and means for supplying working fluid to said nozzle means under a pressure of at least 15 lbs/sq. inch by way of the liquid jacket.

13. In a vapour-stream vacuum pump em ploying as working fluid aniorganic liquid having at room temperature a. relatively low vapour pressure, a body having a liquid jacket, nozzle means adapted to emit a stream of vapourised working fluid within said body for effecting pumping action, working fluid storage means, and means for supplying working fluid to said nozzle means by way of the liquid jacket.

14. An arrangement for evacuating a vessel, comprising a high vacuum connection on said vessel, a backin pump, a plurality of conduit lengths of progressively smaller bore extending between said high vacuum connection and said backing pump and sloping downwards towards said backing pump, nozzle means disposed within each conduit length and directed away from said high vacuum connection, working fluid storage means, means for supplying working fluid to said nozzle means, and means for returning working fluid discharged'through" said nozzle means to said storage means.

15. In a fluid stream vacuum pump employing as working fluid an organic liquid having at room temperature a relatively low vapour pressure; unitary flash boiler and nozzle means; and means to supply working fluid to said unitary flash boiler and nozzle means at a pressure of at least fifteen pounds per square inch absolute.

16. In a fluid stream vacuum pump employing ,as working fluid an organic liquid having at :conductlve tube arran working fluid to said nozzle means means to pass an electrical current of high-amperage through -t pp1y vapourized said tube to eflectheating thereof; and means to supply working fluid to said boilermeans at a pressure of at least fifteen. pounds per square inch absolute. 7

17. A fluid stream vacuum pump comprising a pump body havinga high vacuum connection and a fore-vacuum connection respectively ad- 'jacent its opposite ends, a low pressure nozzle arrangedwithin' said body and directed towards the fore-vacuum end thereof, a high pressure nozzle arranged within said body between said low pressurenozzleand the; fore-vacuum end of the body and directedtowards said fore-vacuum end, meanstosupply vapourized working fluid to said low pressure nozzle at a pressure of at least fifteen pounds per square'inch absolute,

and meansto supply working fluid-in liquid phase to said high pressure nozzle at a pressure of at least fifteen pounds per square inch absolute.

13. An arrangement for evacuating a vessel,

comprising a high vacuum connection on said vessel, a backing pump, a conduit length extending between said backing pump and said high vacuum connection and sloping downwards towards said backing pump, a unitary flash boiler and nozzle disposed within said conduit length and directed awayfrom said high vacuum connection, working fluidstorage means, means for supplying working fluid on liquid phase at a pressure of at least fifteen pounds persquare inch absolute to-said unitary boiler and nozzle, and means for returning working fluid discharged throughthe nozzle to said storage means.

19. An arrangement for evacuating a vessel, comprising a highvacuum connection on said vessel, a backing pump, a plurality of conduit lengths of progressively smaller'bore extending REFERENCES oirnn The following references are of record in the 'file of this patent:

UNITED STATES PATENTS Number Name Date 743,103 Ray Nov. 3, 1903 2,028,340 Lewis a' Jan. 21, 1936 2,338,583 Hickman et a1. Jan. 4, 1944.- 2,558,067 Hickmane= Sept. 12, 1944 2,379,436 -Hickman:et al. July 3, 1945 640,463 Gildea z -Jan.'2, 1900 

